Sighting-telescope.



No. 888,888. PATENTBD MAY 5, 1808.

M. DA s. NETTO. I SIGHTING TELESGOPE.

APPLICATION FILED JAN. 8, 1907.

UNTTED sTATns PATENT oFFion MARIO DA SILVEIRA NETTO, OF PARIS, FRANCE, ASSIGNOR TO FRIED. {(RUPP AKFIENGESELLS(HAFT, OF ESSEN-(')N-'ll'lE-'Rl'lllt` GERMANY.

SIGHTING-TE LESCOPE Application filed January 8, 19.07. Serial No. 351,333.

T all whom .it may concern:

Be it known that I, MARIO DA SILVEIRA NETTO, a citizen of the Republic of Brazil, and a resid ent of Paris, France, have invented certain new and useful Improvements in Sighting-Telescopes, of which' the following is a specification.

The present invention relates to those sighting telescopes which are provided with a device for illustrating the sighting mark (hair-cross or the like) in order to make it possible to use the telescope in darkness.

A The hitherto known sighting telescopes of this type have the drawbback that the sighting field of the telescope, when the illuminating device is used, becomes so glary that the eye of the observer becomes blinded, and consequently observes very badly or not at all the image of the object to be aimed at.

The object of the lnvention is to avoid this drawback.

One embodiment of the invention is shown in the accompanying drawing, by the way of example.

Figure 1 shows a top view, partly in section, of the sighting telescope, and Fig. 2 is a section on line 2-2, Fig. l.

The optical arrangement of the sighting telescope, which in the drawing is shown as a prism-telescope by the way of example, is old and therefore need not be described in detail.

In the proximity of the focal plane of the objective, a glass plate A carrying a sighting mark a. (F ig. 2) is arranged in the usual manner. The sighting mark a/ consists of two intersecting rows of dots, the dots ofl each row being equidistant. lThe glass plate A is of circular form and has straight polished faces. which surrounds the glass plate A is provided with an aperture B which is completely closed towards the interior by the curved face of the glass plate A. That part of the curved surface of the glass plate A that is exposed to the aperture B is transparent while the remaining part of the curvedv surface is made reflecting by means of a suitable coating. On the outer side the aperture B is covered, in a bell-like manner, by a sleeve or casing C secured to the housing of the telescope and closed towards the exterior by means of a cover C which is rigid with the sleeve. In the sleeve C, and directly in front of the ap- Specicaton of Letters Patent.

That part of the telescope housing Patented May 5, 190s.

erture B, is arranged a transparent disk l) which is colored red. (')n the inner sideI of the cover C is secured an electric lamp E.

The white rays of light that are emitted from the electric lamp E hit the transparent red disk l) which allows the red rays of light to pass through while it absorbs all the other differently colored rays of which the white light is composed. The red rays which pass out from the transparent disk l) reach the glass plate A throughthe aperture B and enter the glass plate through the transparent part of the curved surface of the plate. The majority of the entering rays of light strike the straight faces of the glass plate A, partly directly and partly -after being reflected on the reflecting lpart of the curved surface of the plate A. The rays become totally reilected on the straight faces of the glass plate and being reflected over and over again spread. over the entire plate. As the rays of light continuously are subject to total reection on the straight faces of the )late 'A the rays cannot emerge from the p ate A, in the direction of the axis of the eye-piece vand they therefore lbecome invisible to the eye of the observer. Only at those places where are located the dots forming the sighting mark, does a dispersion of the light take place, as the surface 1s rough, at those places, and the rays of light spread in all directions and consequently in the direction of the axisA of the eye-piece. The dots of the sighting mark, therefore, are clearly visible and appear in red color. The red rays of light that emerge fromv the dots of the sighting mark also illuminate of course the glass plate A, but the illumination of the late is so weak that it cannot have any disturbing effect, as, on the one hand, the red light has only small lighting power and, on the other hand, the luminous surfaces have only .yery small area as they merely consist of a number of dots. When the telescope is used in darkness the objects to be laimed at are therefore almost as clearly visible when the sighting mark is illuminatedas when it is not illuminated. g

It is further to be noted that the sighting telescope can also be used as a distance meter. The image of the target which is formed in 4the telescope can be measured as with a size. of the target is known, the. distanee can be obtained in the known manner l'roni the size ot' the image.

ltI is evident that the red colored transparent disk l) could be replaced b v a tiansv parent disk ol' another suitable eolor without.

any departure from the spirit ot' the invention. vlt is merely essential that the colored light entering the glass plate A has small lighting power. It a source of light is used which in itselt radiates light of a suitable color the eolored transparent disk eantherefore be omitted. lt is not absolutely necessar to have the sighting mark consisting' ot' dots as even when l'ull lines are used a disturbing illumination of the sighting lield 'does not take place in spite of tho increase l of the luminous surfaces, as the rays of lightI yemployed possess only small lightingl power.

Having thus described my invention, what l claim, and desire to secure by Letters Patent is: I 1. The Combination with a sighting teleg seope having' ar glass plate Carrying a sight- ,I ing niark, ofl a lightl arranged to illuminate E the sighting' mark, anda colored transparent'. material arrange-d betweentho light and the glass plat-e.

2. The combination of a sighting telescope, having a glass plate carrying av sighting niark consisting ot a number ot dots, and

means for illuminating the sighting mark.

Si The combination of a. sighting telescope,

having a glass plat-el carrying' a sighting niark, the telescope being formed with an aperture closed at its'inner end by the edge ol' t-lie glass plat-e, a rellecting material on those edges ol the plate unexposed to the aperture, a easing' iiiclosing the outer end of the a-perturea light arranged within the easing, `and av colored transparent material arrangedbe ween the light and the glass plate.

The foregoing speeifieat'ioii signed at Paris, France, this 26th da)Y ot' Deeemb r, 1906.

ln presence oll- JoiiN BAKER, IlANsoN (I. (oxE. 

